Approximately 50,000 peripheral artery embolization procedures are performed annually in the U.S. for a variety of clinical indications including stopping life-threatening bleeding; reducing blood flow to cancerous tumors; and diverting blood away from arterial aneurysms, arteriovenous fistulas, and other vascular malformations. Most of these procedures involve the implantation of wire coils or wire mesh vascular plugs to stimulate the formation of thrombus, resulting in blood vessel occlusion. These devices are difficult to place accurately, require substantial time and effort to achieve complete occlusion, and can be susceptible to vessel recanalization, all of which can reduce the overall effectiveness of the treatment. Metactive Medical, Inc. is developing the Blockstent Microcatheter(tm), an innovative embolic medical device that is easy to use; can be placed with a high degree of precision; and results in immediate, complete, and sustained blood vessel occlusion. Based upon highly successful pilot nonclinical studies, Metactive believes the Blockstent Microcatheter has the potential to enable more precise device placement; faster, more complete, and more durable blood vessel occlusion; and fewer complications relative to currently available devices such as coils and vascular plugs. The objective of this proposed Phase I program is to compare the performance of the Blockstent, coils and vascular plugs in canine models of vascular occlusion. A planned Phase II program includes finalizing the Blockstent design in a range of sizes, performing design for manufacturing activities, completing design verification & validation, developing a quality management system, and launching first commercial sales of the device.